Objectives: 1. Determination of the sites of biosynthesis of spermidine in plants infected by turnip yellow mosaic virus. 2. Characterization of enzymes of spermidine synthesis in virus-infected plants and in blue-green algae. 3. Attempted infection of blue-green algae by RNA of R17 and turnip yellow mosaic virus. 4. Study of RNA multiplication in virus-infected plants. 5. Continuing study of the relation of RNA synthesis to bleomycin toxicity in E. coli and mouse fibroblasts. 6. Continuing study of the regulatory role of guanosine tetraphosphate in putrescine and RNA synthesis in E coli.